Automatic liquid sample dispenser



Oct. 26, 1954 F. WARREN 2,692,502

AUTOMATIC LIQUID SAMPLE DISPENSER Filed Feb. 24, 1953 2 Shee tS-Sheet l ii Z flv i 5 A3 r 6 f K J O "6 24 43 l? 25 INVENTOR. 5190 H Mrren Oct. 26, 1954 F. H. WARREN 2,692,502

AUTOMATIC LIQUID SAMPLE DISPENSER Filed Feb. 24, 1953 2 Sheets-Sheet 2 A /00 F f /0/ SEQUENCE TIMER 402 /0 5 5wrrcH r''1 L J //2 Eccswrmcs l "k V316? 84 I 85 47 ea/ Fred H. War/en @u-mfi W Patented Oct. 26, 1954 UNITED STATE 2,692,502 AUTOMATIC LIQUID SAMPLE DISPENSEE Fred H. Warren, Findlay, Ohio H H Application February 24, 195 3, 338,229.

This application is a continuation-in-part of my prior application Serial No. 284,239, filed April 25, 1952, which has been abandoned in favor of the present application.

This invention relates to means for dispensing measured quantities of liquids, and is intended primarily for use in the oil industry to obtain successive oil samples for testing purposes, but is not restricted to such use.

In 'many industries it is customary to remove a smallquantity of liquid from a stream flowing from a pipe or conduit for quality determination or control. Each sample withdrawn from the stream must be of uniform volume and may be taken at regular intervals as to time, or proportionally to rate of flow. It has been common in the oil industry to withdraw a one-half pint oil sample manually each hour from a uniformly flowing stream and pour it into a two gallon sample can after first having cleared the sampling line of liquid remaining from a previous sample by drawing it into a waste liquid container or sump. This method will produce a sample particularly representative of the stream at the instant of sampling but is subject to irregularities due to the human element and is too expensive if samples are taken frequently enough to give a representative sample of the entire stream. With volatile materials much evaporation results from repeatedly removing the sample can lid and from exposure to the air while pouring from the cup to the sample can.

Many designs of automatic samplers are in use today in the oil industry, some of which clear the sampling line of liquid from the previous sample andsome do'not. One of the earlier designs uses solenoid operated valves controlled by a'sequence timer. The machines usually clear the sampling line before taking a sample, but are obectionable for the reason that the size of the sample must be regulated (1) by the time the sampling valve remains open, and (2) by using a throttle valve between the line being sampled and the sampler, which causes the size of each sample to vary as the line pressure varies. Furthermore, this type of sampler is not suitable for sampling high pressure streams, as the sample is discharged into the sample can at high velocity which creates turbulence and causes evaporation losses.

Another common type of automatic sampler,

of which there are several variations in design,

employs a small motor-driven direct-acting pump, which actually pumps liquid out of the line. This is generally referred to as a continuous sampler because the pump operates continuously and takes many very'small samples each min- 18 Claims. (Cl, 73-422) 2 ute. This type is objectionable, particularly when used in'connection with oil'strea'ms, "as the pump valves and passages are so'sniall' that they become clogged in service and 'ther'e'isa tendency for compositesamples taken therewith to run low inimpurlties,indicating that someseparation takesplace in the sampling line.

" The obje'ct of "the present invention is the provision of an improved sampler'of the character described which obviates the'above-noted-objec'tions in the use of. samplers now generally used. r

Further objects of the invention are the provision of a device'offthischaracter which is automatically operable to withdraw samples of, uniform volume from a flowing liquid stream regardless of the pressure therein; alsb the provision 'in such a device ofautomatic means for clearing the'sampling l'ineand sampler of all liquid remaining-from the previous sample; of means ior'trapping'aportion of the column of liquid flowing through the sampling linewhile still'in motion so that all foreign matter-,such as sedimentandwater carried in the liquid, will be held in suspension untilfthe' sample has been taken, and of means for transferring the samples to' the sample can without turbulence so as to minimize loss of liquid by evaporation:

Other objects and advantages of the invention will be apparent from the followingdetailed description; and from the accompanying drawings illustrating the inventionf'and irrwhich- Fig; '1 'isan'elevati'on'of a sampler embodying the invention, with'parts brokenawayandin section and with the moving parts in the at-rest position they assumeat the 'end of a sample taking" cyclej Figl2is' a similar view of the valve parts with the valves in positionior clearing thesampling line after'a previous sample has been taken; Fig.3 is an 'elevationof a difierent embodiment of the invention, 'wi th'pa'rts broken away and the electric wiring diagrammatically shown, and with the valves in sample releasing positions corresponding'to the valve positions'in Fig.1;

' Fig. 4 is a fragmentary view of the valve structure, with parts i'n'sectioh and with the valves in positionscorresponding to the positions of the valve's in'Figj2,"a'nd"""" Fig. 5'i's 'an eiil'arged sectional detail of the Operation controlling limit Switch-J One illustrated apparatusembodying the invention, andshown in Figsiland 2, includes an admission 'and'vent valve unit A, *a distributor valve'unit B, a'sa'mple metering connection C be tween the units A and B, a sample can D, which receives metered samples from the distributor valve B, and the operating and control means E for the valves.

The sampling and vent valve unit A comprises a preferably cylindrical stationary body or casing 5 having one end, its top in the present instance, open and its opposite end provided with a restricted outlet passage 2. The flowing or supply line for the sampler is designated 3, and this communicates with the interior of the casing I through a side thereof and adjacent to the outlet passage 2. A cross-head t of cylindrical form is mounted in the casing I for longitudinal reciprocatory movements therein and with its inner end terminating adjacent to the inlet from the supply line 3. This cross-head is sealed against leakage of fluid pressure therearound within the casing I, and has a closed outer end and an axial bore 5 extending from its inner to near its outer end.

An admission valve 5 is disposed in the closed end portion of the casing l and is adapted to seat on a raised annular shoulder I to close the communication between the outlet 2 and the inlet from the pipe 3 a distance inwardly from the former, thus providing a space 8 at the inlet end of the casing. The valve 6 is carried by a stem 9 which extends into the bore 5 of the member i and has a sliding leak-proof fit therein. A coiled expansion spring in in the inner end of said bore acts against the stem and holds the valve yieldingly seated on the shoulder 7 when the member A is at the inner end of its stroke in the casing l.

A passage l I extends axially through the valve 6 and its stem, and the lower end of this passage or that which opens into the space 8 is closed by a vent valve l2 when the valve 6 is raised from its seat by an outward movement of the member 4, as shown in Fig. 2. The stem !3 of the valve l2 projects freely through the passage l l to provide a vent space therebetween, and the opposite or inner end of the stem projects axially through the spring [0 and is threaded or otherwise suitably anchored in the outer end portion of the member A, so that the valve and member move together in the casing i. The inner end portion of the stem i3 has a vent passage 14 therein that opens at one end to the vent space around the stem and at its other end communicates with a tube [5, preferably flexible, that extends to and opens into the interior of the sample can D.

The distributor valve unit B is located below the unit A. and comprises spaced upper and lower stationary casing parts It and 49, respectively, between which a slide valve 28 operates. The part l8 has a port 2| in communication with the outlet 2 of the sampling unit A through the sample metering connection C, while the part 19 has a port 22 in communication with the sample can D through a discharge tube 23. The slide valve 26 has a passage 24 therethrough which, when the valve is in one position of its movement, registers with and opens communication between the two ports 2! and 22, as in Fig. 1. The valve also has an angled passage 25 therein which, when the valve is in another position of its movement, opens communication between the port 2i and a drainage pipe 26 leading to any suitable place of disposal of drainage from the sampling system, thus permitting purging of the system of all liquid remaining from the previous sample.

The volume of liquid collected for each sampling operation is determined by the size of the space 8 in the sampling valve unit and the liquidholding capacity of the metering connection C, and this may be varied by changing the inside diameter or length of the tube 28 in said connection.

The sample can D consists of a closed vessel capable of withstanding internal pressure, and has a gland type fitting through which the delivery pipe 23 is projected. It is also provided with a normally closed relief valve 25 and preferably with a stoppered pouring spout 30.

The control and operating means E for the various valves includes a shaft 35 having an eccentric 33 thereon connected by a pitman 3'! to the outer end of the cross-head member 4, whereby an inward and an outward stroke movement is imparted to said member at each complete revolution of the eccentric. The shaft 35 also has a cam drum 38 with a circumferential cam groove 39 therein and in which operates a roller it! carried at one end of a lever ll. This lever is fulcrumed at $2 and has its opposite end connected to the distributing valve 20 by a link i3 so as to impart shifting movements to the valve when the shaft is rotated. The cam groove 39 is so shaped that when the shaft 35 is at rest, after a sample taking cycle, the lever 4! stands in the position shown in Fig. 1 in which the valve passage 24 registers with the casing ports 2| and 22. As the cam 38 starts its rotation at the start of a sampling cycle, and in the direction indicated the arrow, the cam groove 39, in approximately the first movement of the cam, moves the valve 29 to the right so as to move the passage 24 out of, and the drainage passage 25 into, register with the port 2! (as shown in Fig. 2), thus permitting drainage from the sample metering parts, whereby to remove any portions of a previous sample remaining therein. The valve continues in this position during approximately the next 90 movement of the cam 38, and at the end of such movement the cam groove 39 acts on the lever ll to move the valve 20 to a position in which its passages 24 and 25 are at opposite sides of, and both out-of-register with, the port 2!. Such position of the valve is maintained until the cam 38 is near the end of its cycle where the lever 4| is operated to move the valve 20 to sample distributing position in which position the passage 2% registers with the casing ports 2! and 22. This position of the valve is then maintained until the start of the nest sampling cycle.

The shaft 35 is driven by an electric motor 45 through a speed reducer shown conventionally at 46. The starting of the motor may be manually controlled by use of a starting switch, but is preferably effected by a sequence timer (not shown), inasmuch as the present device is for withdrawing samples of uniform volume and at predetermined intervals. Once the sampling cycle is started, the motor circuit will be maintained closed by a holding switch, indicated at 41, and in a manner well understood in the art, until the shaft 35 has completed a single revolution or cycle. The switch ll is controlled from a cam ring 50 on an end of the cam 36 through a roller 51 engaging the inner cam surface of the ring and by a connection 52 with the switch. The manner of driving and controlling the shaft rotation is not in itself new and, therefore, is only more or less conventionally shown.

It will be understood from the foregoing that in the operation of the sampler, the parts thereof are in the positions indicated in Fig. 1 during atrest periods or intervals between cycles and also ne ates;

rotate the shaft 35 and the eccentric 36-will first act-to close the vent valve i2 and then to lift the admission or sampling valve fifrom its seat to permit flow from the pipe 3 into the metering tube 28. Simultaneously, cam groove 39will act on-lever ii to position slide valve 2%} so that waste passage 25 will register with port 2| of the distributor valve and direct the flow of liquid through pipe 25 to a sump or sewer, thus purging the system of all liquid remaining from the previous sample. When the shaft has made approximately one-half a revolution, the admissionvalve fi. will start to close and cam groove 39 will shift lever H to move distributor valve to a position to place valve passages 24 and 25 at opposite sides of port 2!, thus stopping fiow through the valve Zfiand trapping a quantity of liquid in pipe 28 and chamber 8. Cam groove 33 will then hold the valve iii in said intermediate position until after admission valve 5 closes. As the cam shaft continues to rotate, cam groove 39 will move the distributor valve 253 over to align passage 24 with both distributor ports 2! and 22, and eccentric 36 will, at the same moment, push vent valve i2 off its seat. At this point in the operation, cam ring Eil will actuate switch 4'! to open the motor circuit and stop rotation of the shaft. When vent valve I2 opens, the space around its valve stem and the passage id in the stem will permit vent line is to equalize the pressure between the sampling valve 6 and distributor valve 28 so that the sample trapped in such space may drain into sample can D. The sampler parts will then remain in the position shown in Fig. 1 until the start of the next sampling cycle. .t is obvious that the sampling events may be speeded. up or retarded by changing the ratio of the speed. reducer, the speed of the motor, or by introducing a variable speed drive.

It is apparent that the sampling valve 6 with the associated vent valve 52 constitutes means for performing the dual function of admitting a liquid sample from the stream being sampled, and releasing the sample to the can D by per mitting balancing of the pressure both above and below the sample trapped between the admission or sampling valve ii and the distributor valve 28 so it may flow gently into the sample can. A. turbulent discharge and resulting evaporation of the sample is thus prevented. While admission valve t; is held to its seat by the pres-v sure of the spring it], it is contemplated that the diameter of this valve will usually be larger than the valve stem {-3 so as to utilize the unbalanced pressure above and below the valve to hold the valve to its seat.

In the form of the invention shown in Figs. 3, i and. 5, which is simpler and comprises fewer parts than the first illustrated form, the unit F combines the functions of the units A, B and C of said first form, and the sample receiving can G and the operating unit I-I correspond to the can and the control operating unit E of the first form, respectively.

The unit F, in its present embodiment, comprises a block or body 58 having a vertical passage El therethrough in communication at its upper end with a pipe or conduit 52 leading from the line carrying the oil or other liquid being sampled. The passage ti is intercepted by two horizontal bores 63 and 64 spaced lengthwise thereof and forms therebetween the sample me erin en a h weri i h assa e;

6| ris -connected. bya downwardly extending tube 56- to the interior of the. sample can G. Slide; valves 6 and 68 are; mounted, respectively, in. the bores Stand 64,- the former serving as an.

admission valve to the metering space 55. of the passage 6| andthelatter serving as a, distributing valve controlling the discharge. from said space.

The valve 6'! has a cross port 69 therein which, when the vvalveis in open position or at the limit of its stroke to the right, registers withthe passage f5! and permits filling of the metering space 55 from thc-supplyline 62, as shown in-Fig. 4. Thevalve 6B has. a. cross port 79 therein which, when the valve is in openposition or at theforward or right end of its stroke, reg-isterswith the passage ti, as in Fig. 3. The two valves: are operated as hereinafter described to alternately open the passage iii so that when one valve is closed the other is opened.

Thesample can G, the same as in Fig l, com-v prises a closed vessel'capable of withstandingim.

ternal pressure, and has a gland type fitting through which the tube- 66 is projected. It is alsoprovided with a normally closed relief valve' H and a venttube 72 extending from its top. This vent line communicates With the right or forward end of the valve receiving bore 63, and when the valve 61 is closed, such end communicates with the upper-end-of the metering space to the passage GI.

65 of the passage 6! through an angle-passage 73' in the forward end of the valve. In this position the crossport 69 of the valve 6]. is closed It is thus apparent that the upper end of themetering chamber 65 is vented to the can G topermit free flow of the metered liquidto the can when the valve 61 is in closed position and the valve 58 is in open position. with respect to the passage 61,, as shown inFig. 3.

When the valve 68 is in closed position, as shown in Fig. 4, an angle-passage M in its forward, end portion opens communication between the metering space 65 and a drain pipe 15, thus permitting purging of the system of alliliquid ree maining from. the previous sample. The drain. age pipe leads from the forward. end of. the bore 64 to a suitable place of drainage disposal.

It is ap arent that the volume of liquid collected for each sampling operation is determined by the capacity of the metering space 65 in the passage 65, and that this may be varied by changing the size of such space.

The valve control and operating means H shown in Fig. 3 comprises, in the present instance, an electric motor 8!] driving a shaft 81 through a speed reducer 62. This shaft is mounted in suitable bearings at right angles to the axes of the valve bores 63 and 64 and has two eccentrics 84 and 85 connected by pitmans 86 and 8'! to the outer ends of the respective valves 61 and 68. The. throws of the two eccentrics are diametrically opposite so that the valves have reverse movements in unison.

An electric limit switch 99 is mounted in a housing 9! (Fig. 5) and has a cam rotor 92 fixed on the shaft inside the housing and this cam has a depression 93 in its periphery at one side of its axis. A switch arm 94, pivoted at at one side of the cam periphery to an insulation ring 95, carries a roller 91 at its free end in position to ride on the cam periphery of the rotor. 9 .2. An electric switch contact 9 8 is yieldingly carried by the arm 94 and engages a stationary contact 99, to close the switch circuit when the roller is traveling on the concentric portion of the rotor periphery and to open said circuit when the roller is in the depression 93. The ring 96 is rotatably adjustable in the housing and carries the contact 99 is addition to the pivot 95. The depression 93 is short and the roller 91 drops therein immediately at the end of a sample taking cycle, or of one complete rotation of the cam rotor 92, and passes therefrom at the beginning of the next cycle.

The motor 35! is in circuit with electric current supply wires i053 and id! through respective leads I02 and H13, and the switch contacts 98 and 99 are in circuit with the lead its so that the motor starts and stops upon the respective closing and opening of said contacts.

In addition to the switch 9% a sequence tin-er N15 is disposed in the motor circuit in bridging relation to the switch 9%, whereby the motor o crating circuit is periodically closed by such timer and is opened at the end of a cycle by the limit switch 99. The normal at-rest position of the shaft 85 is with the valve 67 in closed and the valve 68 is open position with respect to the passage 6!. During a revolution of the switch cam rotor 92, the positions of the valves and (it are reversed to permit a sample charge of liquid to enter the metering space 05 and the valves are then returned to normal. positions to close the passage 6! to the supply line and open the metering space 65 to the discharge tube 655. At the end of a sample taking cycle the roller 9'! drops into the rotor depression 93 and opens the contacts of the limit switch 90 to stop the drive motor. The motor now remains at-rest until started for the next sample taking cycle by the sequence timer.

In order to release the sample taking unit F of the liquid line pressure, except when receiving a sample charge, a solenoid valve lid is located in th supply line 82 and this solenoid is energized to open the valve during a predetermined portion of each sample taking cycle. In the present instance, the solenoid circuit H! is in connection with the lead wires H39 and Eli and a mercury switch is disposed therein. The mercury container l 52 of this switch is carried by an upright arm of a bell crank lever H3 that is pivoted at M4 on the body Gil. The other arm of this lever rests on aroller H5 carried by the connection between the pitman 86 and the valve 61, whereby the lever is rocked in first one direction and then the other to close and open the circuit by reciprocatory movements of the valve. The closing of the solenoid circuit is timed to take place approximately coincident with or slightly before the opening of the supply line 52 to the metering space 65 of the passage Bl, while its closing takes place during th initial portion of the rearward stroke of the valve.

In each form of the invention an admission valve, 6 in the one case and 37 in the other, is periodically opened to permit a sample charge to pass from the supply line to the metering space, the distributing valve, 2i? in one case and E8 in the other, being closed. During the last half of a sample taking cycle the admission valve in each form closes and the distributing valve opens to permit the liquid sample to discharge into the sample can. At the same time the vent line in each form is opened from the can to the top of the meterin space. Also, in the beginning of a cycle in each case, after a closing of the distributing valve, the metering space is open to the drain to purge the sample dispenser and connecting piping of all liquid before the next sample is taken.

I wish it understood that my invention is not limited. to any specific construction, arrangement or form of the parts, as it is capable of numerous modifications and changes without departing from the spirit of the claims.

What I claim is:

1. A liquid sample dispenser comprising means for connecting a liquid flow line with a sample receiving reservoir, said means including a passage with a sample metering portion, an admission valve bet een the flow line and said metering portion, a distributing valve at the lower end of said portion, mechanism having connections with said valves and operable during a sample taking cycle to open said admission valve and close said distributing valve and then at predetermined points in cycle to close said admission valve and open said oistributing valve, and means providing a vent for the metering portion of said passage and including a valve for automatically opening said vent when the admission valve is closed.

2. A liquid sample dispenser comprising means forming a passage for connecting a liquid flow line with a sample receiver, said means including an admission valve at the receiving end of said passage and a. distributing valve in said passage in spaced relation to said first valve and toward the discharge end of the passage, the space in the passage intermediate said valves forming a sample metering portion, said admission and distributing valve standing in positions to respectively close and open said passages at the starting of a sample takin cycle, means having separate connection with said valves and operable to move said admission valve to open said passage and to move said distributing valve to close said passage during a predetermined initial portion of a cycle and operable during the remaining portion of a cycle to close the admission valve and open the distributing valve, and means for venting said passage between said two valves when the admission valve is closed.

3. A liquid sample dispenser comprising means forming a passage for connecting a liquid flow line with a sample receiver, said means including an admission valve at the receiving end of said passage and a distributing valve in said passage in spaced relation to said first valve and toward the discharge end of the passage, the space in the passage intermediate said valves forming a sample metering portion, said admission and distributing valve standing in positions to respectively close and open said passages at the starting of a sample taking cycle, means having separate connection with said valves and operable to move said admission valve to open said passage and to move said distributing valve to close said passage during a predetermined initial portion of a cycle and operable during the remaining portion of a cycle to close the admission valve and open the distributins valve, said sample receiver constituting a closed receptacle, and means in communication with the interior of the container for automatically venting passage at its inlet end to said container when the admission valve is closed and preventing said venting when said admission valve is open.

1. A liquid sample dispenser for receiving samples under pressure from a flow line, comprising a, closed sample receiver, means forming a passage between the flow line and said receiver and including a sample metering portion, an admission valve at the receiving end and a disrub:

tributing valve at the discharge end of said metering portion, means operable toeopensandxclose each: of said valvesin predetermined:relation whereby at the .beginningof a-sampling cycle the-admission valve isopenedand the distributing valve is closed and near the end -of.the-cycle' the admission valve: is closed and thedistributing valve is opened to dispense a metered sample, means forming a vent passage forthe: metering portion between said valves, a valve for said vent passage, and means operable in synchronized relation-to said admission valve-to move said -vent valve to open said ventpassagewhen the admission valve is closed and to; close the vent passage when the .admissionivalve is: opened.

5. A liquid sample dispenser for receiving samples under pressure from a flow line, compris- =ing a closed sample receiver, means formingra passage between thefiow line-and said receiver and including a. sample metering portion, an admission valve .at thereceiving-end and a distributing valve. at the discharge end of saidmeterportion; means operable to open and close each of said valves in predeterminedrelation: whereby at the beginning of a sample-cycle the admission 1 valve is opened and the distributing valve is closed near the end of the cycle theiadmission valve is first closed and thedistributing valve then opened to dispense a metered sample, means forming a'vent passage for the meteringportion between said valves, a valve forsaid vent passage, means operable in synchronized relation to said admission valve to move saidrvent-valve to open receiver.

6. A liquid sample dispenser, -comprising a closed sample receiving reservoinmeans for/connecting aliquid flow line with said reservoir, said means including a passage with asample-metering portion, an admission valve between the-flow line and said metering portion and a distributing valve at the lower end of said:-prtion,.1mechanism having connections with said valvesand operable during a sample taking cycle, to open said admission valve and close said distributing valve and then at predetermined points in a-cycle to close said admission valve. and open saiddisid .valve. for opening said vent when theadmission valve is closed and. closing the vent when the admission valve is open, means forming .a;dra-in- =age passage from the lower end'of said metering portion, said distributing valve having a passage for opening said drainage. passage. when the distributing valve is in closed-positionand for closing said drainage passage when the distributing valve is in open position .with'respectto. said first-mentionedpassage.

8.. A liquid sample dispenser for receiving samples under pressure fI'Om.a,flOW,1ine,ICOm-' prising. a sample receiver, means forminga pas- "sagebetween the flow. line andsaid receiver and including a sample metering .portion, .anadmission valve at the receiving endlanda distributing. valve at the: discharge end oizsaid .metering portion, means operable toalternatelyxopenand close said valves whereby. at 'the'beginning of a sampling cycle the admissionvalve is openand thedistributing valve is closed and near .the end .of .the cycle the admission valve'is closedand the distributing valve. is, opened toidispensea metered sample to said receiver,:meansproviding a ventbetween said receiver and metering portion of saidpassagaand means operable to open the vent when the admission valve is closed.

. 9., .A liquid sample dispenser for receiving samples under pressure from a 'flow,line, comprising '30 a sample receiver, means. forming apassageba tween theflow line and saidreceiver andsim cludinga sample metering portion, an admission valve at the receiving end and. a:distributing valve ;aat the discharge end of said metering portion,

means' operable toalternately open and close said :valves whereby-at the beginning of ,a sampling cycle the admission valve is-open: and the distributing valve is closed and nearthe end of the :cycle the. admission valve isclosedand the-dis- 40 .tributing valve is opened todispense a metered sample to said receiver, andmeans'providing a vent between said receiver and meteringoportion of said passage, said admissionvalve-having a passage therein which opens thevvent to;.the

5 meteringportion between said, valveswhen the admission valve .isclosed and .wh-ichfcloses .the vent when the admission valve is open.

10. A liquid sample dispenser .for receiving samples under pressure from a flow line, .com-

to; prising a sample receivenn'leans forming apassage between thelfiow line andisaidreceiver and iincluding a samplemetering portionan admission valve at the receiving end and a distributing valve at the; discharge end. of said metering portributing valve, means-providing Eve t b tw tion, means operable to alternatelyopenand the metering portion-of said passage and said reservoir and including a valve in s'aid', admission valve for opening said-vent when the admission valve is closed and closing the vent when the admission valve is open.

'7. A liquid sample dispenser, comprising a closed sample receiving reservoir, means for connecting a liquid flow line with said reservoir, said means including a passage with a sample metering portion, an admission valve-between the -flow line and said metering portion and a distributing valve at the lower end of saidportion, mechanism having connections with said valves and operable during a sample taking cycle to open said admission valve and close said distributing valve and then at predetermined points in a cycle to close said admission valve and open said distributing valve, means providing a vent between the metering portion of said passage and said reservoir and including a valve in said admission close said valveswhereby at the beginning of .a sampling cycle the admission valve is open and the distributing valve is closed and near the end of the, cycle v:the admission valve-is first closed so and the distributing valve is-opened to'dispense a metered. sample to .saida'eceiver, means pro- 4 viding a vent between said receiver. and metering portion of said passage, said admission valve having a passage. therein which opens the. vent to the metering-space between said valves when having a passage which opens said drainage passage to said metering space when the distributing valve is closed and which is closed to said space when the distributing valve is open.

11. In a liquid sample dispenser for taking a sample from a liquid flow line, a. sample receiving reservoir, means connecting said flow line with the reservoir and including a passage with a sample metering portion, an admission valve between the flow line and said metering portion, a distributing valve at the lower end of said portion, mechanism having connections with said valves and operable during a sample taking cycle to open said admission valve and close said distributing valve and later to close said admission valve and open said distributing valve, a valve in said connecting means between the flow line and the admission valve, and means operable by said mechanism to efiect an opening of said fiow line valve during opening movement of the admission valve and to efiect a closing of the valve during a closing movement of the admission valve.

12. In a liquid sample dispenser for taking a sample from a liquid flow line, a sample receiving reservoir, means connecting said flow line with the reservoir and including a passage with a sample metering portion, an admission valve between the fiow line and said metering portion, a distributing valve at the lower end of said metering portion, mechanism having connections with said valves and operable during a sample taking cycle to open said admission valve and close said distributing valve and later to close said admission valve and open said distributing valve, an electric circuit, a solenoid valve in connection with said circuit and normally closing said connecting means between the flow line and the admission valve, a switch in said circuit, and means operable during an opening movement of said admission valve to close said switch and energize said solenoid valve to open the flow line and operable during a closing movement of said admission valve to open said switch.

13. In a liquid sample dispenser having a metering passage for providing communication between a liquid flow stream and a receiver, an admission valve unit including a cylinder at the inlet end of said passage for attaching to a flow line, an admission valve slidably mounted in said cylinder and operable to open and close the inlet end of said passage, said valve having an axial vent passage in communication with said first passage at the outlet side of the valve and with a space exteriorly of said unit, a valve for closing said vent passage and standing open when the admission valve is closed, and means operable during the initial portion of a sample taking cycle to close said vent valve and open said admission valve and during the last portion of such cycle to first close said admission valve and then open the vent valve.

14. In a liquid sample dispenser having a metering passage for providing communication between a liquid flow stream and a sample receiver, an admission valve unit at the inlet end of said passage, said unit comprising a cylinder afiording communication at one end between said passage and a flow stream, a plunger member slidingly movable in said cylinder with one end exposed and having an axial bore in its inner end, an admission valve adapted to seat in the passage communicating end of said cylinder to close said passage and having its stem slidingly mounted in the member bore, said valve and its stem having an axial bore therein open to the passage at the outlet side of the valve, means urging a limited outward movement of said valve relative to the member, a vent valve for closing the passage end of said bore and having a stem projecting through said bore and attaching to said member to move therewith, said bore and said vent valve stem cooperating to form a vent passage from said metering passage through the outlet side of the admission valve to a space externally of said unit, and means operable to impart predetermined axial movements to said vent valve to simultaneously close said vent passage and move the admission valve to open position and to open the vent valve after closing of the admission valve.

15. In a liquid sample dispenser, means forming a metering passage for connecting at its inlet end to a liquid flow pipe, an admission valve normally closing the inlet end of said passage, said passage having a vent at its inlet end, means reciprocable to move said admission valve to open position and simultaneously close said vent and then to permit closing of said admission valve and to open said vent, a distributor valve operable to periodically open and close said metering passage at the outlet side of the metering portion thereof, means for operating said reciprocable means, and means operating in predetermined timed relation to said last means to periodically move said distributor valve to close and to open the outlet end of said passage.

16. A combination as called for in claim 15, together with a closed container into which samples are discharged from said passage and with which said vent has communication.

17. In a liquid sample dispenser having means forming a sample metering passage between a liquid flow supply and a sample receiving container, said passage having a vent in communication with the container, an admission valve normally closing the inlet end of said passage, a vent valve, means operable to impart predetermined movements to said vent valve to simultaneously close said vent and to open said admission valve and then after a predetermined pause to permit closing of the admission valve and to open the vent valve, a distributing valve movable into passage opening and closing positions, and means synchronized with said first means to operate said last valve to close said passage when the admission valve is open and to open the passage at approximately the time of closing of the admission valve.

18. A combination as called for in claim 17, wherein said distributor valve has a drainage passage which is open to said first passage during a portion of the period such valve is in the firstmentioned closed relation to the first passage.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,553,215 Christenson Sept. 8, 1925 1,594,052 Draver July 2"], 1926 2,183,338 Slough Dec. 12, 1939 2,411,837 Stephens Nov. 26, 1946 2,534,489 Webber et a1 Dec. 19, 1950 2,548,139 Blum Apr. 10, 1951 

